The invention relates to a steering wheel for actuating a steering movement of a vehicle. With respect to the prior art, by way of example, reference is made to GB 357 614 A, GB 468 489 A and, in particular, to DE 10 2004 046 321 A1.
Conventional steering wheels which are currently used in vehicles, in particular in motor vehicles, can be adjusted in the direction of the steering wheel column axis to an optimum steering wheel position via a steering wheel column, on which the steering wheel is mounted, for adaptation to different body sizes of the vehicle drivers. The height and length adjusting apparatus of the steering wheel column is usually integrated into the steering wheel column housing here. The positional adaptation takes place either manually or with the aid of electric motors, spindles, a gearwheel mechanism or rotary closures.
Here, the steering wheel itself usually comprises a steering wheel hub and a steering wheel rim, and spokes which connect the two. In addition to flat steering wheels, dished steering wheels are also known from the prior art. Said dished steering wheels are distinguished by the fact that the steering wheel hub is spaced apart from the steering wheel rim, as viewed along the steering wheel column axis. Here, the spokes accordingly run not only in the radial direction, as is the case in flat steering wheels, but rather also in the axial direction of the steering wheel or the steering wheel column, for which reason the steering wheel is of dished configuration.
This positional adjustment of the steering wheel column, which is also known under the designation of a telescopic steering wheel column, can take place, as has already been described, either manually or with the aid of suitable actuators such as, for example, an electric motor.
It is a disadvantage of the telescopic steering wheel columns, however, that they take up a large amount of installation space and do not provide the required flexibility with regard to future driving concepts, such as, for example, autonomous driving.
In addition to the described concept of telescopic steering wheel columns, steering wheels are also known, in the case of which the adaptation of the spacing between the upper body and the steering wheel rim can be set by way of adjustment of the spacing between the steering wheel hub and the steering wheel rim. For example, GB 357 614 A and GB 468 489 A describe a dished steering wheel, in the case of which the spokes can be telescoped, and therefore the spacing between the steering wheel hub and the steering wheel rim can be set individually as desired. Whereas said setting takes place manually in the case of the two last-mentioned documents, DE 10 2004 046 321 A1 proposes a steering wheel, in the case of which at least one section of the steering wheel rim can be adjusted in its position with respect to a steering wheel main body by means of an adjusting mechanism, more precisely by means of a drive.
It is a disadvantage of said prior art, however, that the use of one drive per spoke entails an increased installation space requirement. This is because there is only a small amount of installation space for the integration of further components, in particular, in the steering wheel region, on account of the necessary integration of safety components, such as, for example, an airbag.
It is therefore an object of the invention to provide a steering wheel which makes a comfortable adjusting mechanism for adaptation to body sizes possible, it being possible for the adjusting mechanism to be integrated into the steering wheel in as satisfactory a way as possible and using a small amount of required installation space.
The object is achieved by way of a steering wheel for actuating a steering movement of a vehicle in accordance with embodiments of the invention.
A steering wheel is proposed which, in addition to a steering wheel hub for mounting the steering wheel on a vehicle, comprises a steering wheel rim and at least two spokes which connect the steering wheel rim to the steering wheel hub. The spokes can be telescoped by use of a suitable drive, it being possible for the steering wheel rim to be displaced with respect to the steering wheel hub in the direction of the rotational axis of the steering wheel. According to the invention, the drive comprises a single drive motor for actuating at least two spokes.
Here, the telescopic steering wheel spokes make an axial displacement (that is to say, as viewed in the direction of the rotational axis of the steering wheel) of the steering wheel rim with respect to the steering wheel hub possible. A radial displacement or length change of the steering wheel spokes is preferably not provided on account of the rigid geometry of the steering wheel rim.
In one preferred embodiment of the invention, each spoke in each case comprises a movable part segment and in each case a fixed part segment. Here, the two part segments are preferably arranged inside one another, it being possible for the movable part segment of the spoke to be telescoped or displaced or moved in each case relative to the fixed part segment of the spoke.
For example, three spokes of the stated type can be arranged between the steering wheel rim and the steering wheel hub, which spokes for their part are preferably configured in a tube-like manner or in the form of a hub cylinder.
In a further preferred refinement of the invention, the spokes (or at least two spokes) are connected in each case pivotably to the steering wheel rim and to the steering wheel hub. Here, the fixed part segment of each spoke is preferably connected pivotably to the steering wheel hub, and the movable part segment of each spoke is connected pivotably to the steering wheel rim. The respective part segments can thus be attached, for example, by way of a rotary joint or a hinge to the steering wheel rim and to the steering wheel hub. Here, the rotational axis of the pivotable connection runs in the direction of a tangent of the virtual turning circle of the steering wheel. The system is statically defined by way of said pivotable connection of the respective part segments of a spoke, it being possible for a space change between the steering wheel hub and the steering wheel rim in the direction of the rotational axis of the steering wheel to be made possible by way of the extension or shortening of the spokes.
In a preferred embodiment of the invention, the drive motor for bringing about a length change of at least two spokes is arranged in the steering wheel hub. From there, the drive motor can then actuate or drive at least two of the spokes for the length change.
Here, the at least two spokes which are actuated by the drive motor are preferably coupled to the drive motor by a coupling apparatus. A coupling apparatus of this type ensures a synchronized length change of the at least two spokes. Accordingly, at least two (preferably three) spokes are coupled to one another in such a way that their length change is always identical.
The coupling apparatus can be realized here in different ways.
A first possibility of coupling the spokes of the steering wheel to the drive motor and at the same time of ensuring a synchronized length change is the use of a coupling rod. A coupling rod of this type can be arranged, for example, on the rotary joints or on the hinges which connect the steering wheel hub to one of the two part segments of the spoke. In the case of the configuration of, for example, two spokes on a steering wheel, the coupling rod can be connected fixedly at one end to the rotary joint of the first spoke and at the other end to the rotary joint of the second side. The attachment point of the ends of the coupling rod on the rotary joints is preferably arranged eccentrically and at different points of the two rotary joints. Thus, for example, the attachment point of the one end of the coupling rod can be arranged eccentrically on the first rotary joint and (as viewed in the vehicle vertical direction) above the rotational axis thereof, and the other end of the coupling rod can be arranged eccentrically on the other rotary joint and (as viewed in the vehicle vertical direction) below the rotational axis thereof. Here, the drive motor can be arranged on one of the rotary joints and can drive only one of the spokes. In the case of a length change of the first spoke, which length change is brought about by the drive motor, the first steering wheel hub-side rotary joint of said first spoke rotates. By way of a described coupling to the steering wheel hub-side rotary joint of the other spoke, this also rotates, for which reason the rotary angle of the two spokes changes synchronously. A simultaneous and uniform length change of the spokes with respect to one another can be realized in a simple manner by way of the mechanical coupling of the rotary joints by way of a coupling rod. Here, the coupling of the spokes by means of the principle of said coupling rod is in no way restricted to two spokes, but rather can likewise be applied in the case of more than two spokes by way of a minor structural change.
A second possibility for configuring the coupling apparatus is the use of a flexible shaft. Flexible or pliable shafts of this type are known in the automotive sector, for example, in the case of the adjustment of seat positions, filler caps, handbrake cables and much more. They represent flexible connecting elements for the radial electromechanical transmission of force. Here, for example, a flexible shaft of this type can be coupled directly to the drive motor and the spokes. The flexible shaft can in turn (in the case of an embodiment having two spokes) be coupled by way of in each case one end, for example by way of a gearwheel or a bevel gear, to in each case one spoke, and can then drive said spoke in a synchronized manner. The rotational movement of the drive motor or its output shaft which, in this case, is coupled directly to the flexible shaft, can thus be converted by means of a suitable mechanism at the spokes into a synchronized translational movement of at least two spokes.
In another preferred embodiment of the invention, in addition to the two abovementioned possibilities, the coupling apparatus can be configured as a flexible drive mechanism. For example, it can be configured as a belt mechanism.
Here, it is possible, for example, that the drive motor drives a drive belt, which drive belt in turn transmits or introduces the force into the spoke in each case via a pinion or a bevel pinion. In the case of an embodiment of the invention with more than two spokes, for example in the case of three spokes, the output shaft of the drive motor can drive a first spoke directly, whereas the other two spokes are driven by means of said drive belt with the aid of a toothed belt pulley.
For the transmission of the force or the movement from the drive belt or from the flexible drive mechanism to the respective spokes, for example, the bevel pinion or else a spur pinion can be used depending on the embodiment of the telescopic spokes.
It is provided in one preferred embodiment of the invention to couple the coupling apparatus to a spindle thread which is arranged on the spokes of the steering wheel. In the case of said embodiment of the spokes, it is preferred that the coupling apparatus, that is to say, for example, the drive belt, drives in each case one bevel pinion per spoke. The rotational axis of the bevel pinion then corresponds to the rotational axis of the steering wheel hub-side rotary joint or hinge. The rotational movement of the bevel pinion can be transmitted to a bevel gear which is in turn connected fixedly to a spindle in the spoke of the steering wheel. Depending on the rotational direction of the bevel pinion, the movable part segment of the spoke can thus be moved or shifted relative to the fixed part segment of the spoke away from the latter or into the latter. This displacement thus advantageously brings about a change in the spacing between the steering wheel rim and the steering wheel hub.
As an alternative to the last-mentioned embodiment, a spur pinion can likewise be used instead of the bevel pinion, in the case of which spur pinion the rotational axis likewise corresponds to that of the steering wheel hub-side rotary joint or hinge.
In a further preferred embodiment of the invention, the coupling apparatus is coupled to a flexible drive mechanism which is arranged on the spokes, that is to say, for example, a belt. Here, the spur pinion can once again drive a belt which is arranged in the fixed part segment (that is to say, that one which is connected, for example, to the steering wheel hub) of the spoke. By use of a suitable transmission apparatus, such as, for example, a toothed pinion, the movable part segment can then be driven or moved, for example, by means of a rack. Depending on the rotational direction, the fixed part segment of the spoke can thus be moved into the movable part segment or out of the latter.
Instead of the last-mentioned belt-driven toothed pinion, a belt which is toothed on both sides is likewise conceivable, the outer toothing system of which belt engages directly into that of the rack.
An electromechanical adjustment of the steering wheel with only one drive motor can also be achieved in a mechanically simple way in the case of said embodiment of the invention.
A further advantage of the technology according to the invention is that the length-adjustable telescopic spokes can be used in addition to an existing length adjustment via the steering wheel column, the axial adjusting travel being increased, and it being possible for the adaptation to different body sizes or body dimensions to be set in a more individual manner. As a result, ergonomic and health advantages can be achieved for the vehicle driver during driving.
In the case of the use of the construction according to the invention as a sole axial positioning possibility of the steering wheel, the length adjusting mechanism in the steering wheel column housing can be dispensed with. The housing can therefore be of more space-saving design, which in turn has a positive effect on the freedom of movement of the driver. With regard to possible future technologies such as, for example, autonomous driving, in the case of which the steering wheel is then only to be used optionally, the steering wheel according to the invention and the associated enlarged passenger compartment are of great advantage. In addition, a simpler folding-out or extending mechanism of the steering wheel is possible.
Regardless of future technologies, the increased installation space which is associated with the technology according to the invention can be utilized for the integration of other components, such as, for example, a head up display.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.